THS3001 High Speed Current Feedback Operational Amplifier Evaluation Module User's Guide March 1999 Mixed-Signal Products SLOU021A IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI's standard warranty. Testing and other quality control techniques are utilized to the extent TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE ("CRITICAL APPLICATIONS"). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERSTOOD TO BE FULLY AT THE CUSTOMER'S RISK. In order to minimize risks associated with the customer's applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual property right of TI covering or relating to any combination, machine, or process in which such semiconductor products or services might be or are used. TI's publication of information regarding any third party's products or services does not constitute TI's approval, warranty or endorsement thereof. Copyright 1999, Texas Instruments Incorporated Preface Related Documentation From Texas Instruments J THS3001 HIGH-SPEED CURRENT-FEEDBACK OPERATIONAL AMPLIFIER (literature number SLOS217) This is the data sheet for the THS3001 operational amplifier integrated circuit that is used in the THS3001 evaluation module. FCC Warning This equipment is intended for use in a laboratory test environment only. It generates, uses, and can radiate radio frequency energy and has not been tested for compliance with the limits of computing devices pursuant to subpart J of part 15 of FCC rules, which are designed to provide reasonable protection against radio frequency interference. Operation of this equipment in other environments may cause interference with radio communications, in which case the user at his own expense will be required to take whatever measures may be required to correct this interference. Trademarks TI is a trademark of Texas Instruments Incorporated. Chapter Title--Attribute Reference iii iv Running Title--Attribute Reference Contents 1 General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 THS3001 EVM Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 Using The THS3001 EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 THS3001 EVM Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.6 General High-Speed Amplifier Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 1-2 1-2 1-5 1-6 1-7 1-8 2 Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 THS3001 High-Speed Operational Amplifier EVM Parts List . . . . . . . . . . . . . . . . . . . . . . 2.2 THS3001 EVM Board Layouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 THS3001 Rev. A High-Speed Operational Amplifier EVM Parts List . . . . . . . . . . . . . . . 2.4 THS3001 Rev. A. EVM Board Layouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 2-2 2-2 2-4 2-4 Figures 1-1 1-2 1-3 1-4 1-5 1-6 2-1 2-2 2-3 2-4 2-5 2-6 THS3001 Evaluation Module - Original Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . THS3001 Rev. A Evaluation Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . THS3001 EVM Schematic - Original Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . THS3001 Rev. A EVM Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . THS3001 EVM Frequency Response with Gain = 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . THS3001 EVM Frequency Response with Inverting Gain = 1 . . . . . . . . . . . . . . . . . . . . . . . THS3001 EVM Component Placement Silkscreen and Solder Pads . . . . . . . . . . . . . . . . . THS3001 EVM PC Board Layout - Component Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . THS3001 EVM PC Board Layout - Back Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . THS3001 Rev. A EVM Component Placement Silkscreen and Solder Pads . . . . . . . . . . . THS3001 Rev. A EVM PC Board Layout - Component Side . . . . . . . . . . . . . . . . . . . . . . . . THS3001 Rev. A EVM PC Board Layout - Back Side . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1-3 1-3 1-4 1-7 1-7 2-2 2-3 2-3 2-4 2-5 2-5 Tables 2-1 2-2 THS3001 EVM Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 THS3001 Rev. A EVM Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 Contents v vi Chapter 1 General Information This chapter details the Texas Instruments (TI) THS3001 high-speed operational amplifier evaluation module (EVM), SLOP130. It includes a list of EVM features, a brief description of the module illustrated with a pictorial and a schematic diagram, EVM specifications, details on connecting and using the EVM, and a discussion on high-speed amplifier design considerations. Topic Page 1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 1.3 THS3001 EVM Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5 1.4 Using The THS3001 EVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6 1.5 THS3001 EVM Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7 1.6 General High-Speed Amplifier Design Considerations . . . . . . . . . . . 1-8 General Information 1-1 Features 1.1 Features THS3001 operational amplifier EVM features include: J J J J J J J High Bandwidth -- 340 MHz, - 3 dB at 15 VCC & Gain = 2 5-V to 15-V Operation Inverting and Noninverting Single-Ended Inputs Module Gain Set to + 2 (Noninverting) and -1 (Inverting) -- Adjustable Through Component Change. Nominal 50- Impedance Inputs and Outputs Standard SMA Miniature RF Connectors Good Example of High-Speed Amplifier Design and Layout 1.2 Description The TI THS3001 high-speed current-feedback operational amplifier evaluation module (EVM) is a complete high-speed amplifier circuit. It consists of the TI THS3001 high-speed current-feedback operational amplifier IC, along with a small number of passive parts, mounted on a small circuit board measuring approximately 1.7 inch by 1.4 inch. The EVM uses standard SMA miniature RF connectors for inputs and outputs and is completely assembled, fully tested, and ready to use -- just connect it to power, a signal source, and a load (if desired). Two versions of the THS3001 EVM are available. The original appears in Figure 1-1 and the Rev. A version appears in Figure 1-2. Figure 1-1. THS3001 Evaluation Module - Original Version -VCC +VCC GND J3 C3 -IN R5 + + C1 R1 INVERTING U1 C2 J2 R4 NONINVERTING OUT GND GND R2 C4 R3 +IN GND J1 LITERATURE NO SLOP 130 009957 1-2 THS3001 EVM General Information Description Figure 1-2. THS3001 Rev. A Evaluation Module J1 -VCC J2 +VCC C1 C2 GND -IN GND INVERTING TEXAS INSTRUMENTS J4 C3 R4 +IN R1 R3 U1 R5 C4 GND J3 OUT NONINVERTING GND Rev. A + + R2 SLOP130 Rev A THS3001 EVM Board The THS3001 EVM is equipped with both noninverting and inverting inputs. The noninverting input is set for a gain of 2 and the inverting input is set for a gain of 1. Each input is terminated with a 50- resistor to provide correct line impedance matching (Figure 1-3 for original version and Figure 1-4 for Rev. A). The amplifier IC output is routed through a 50- resistor both to provide correct line impedance matching and to help isolate capacitive loading on the output of the amplifier. Capacitive loading directly on the output of the IC decreases the amplifier's phase margin and can result in peaking or oscillations. Figure 1-3. THS3001 EVM Schematic - Original Version VCC C2 0.1 F C1 6.8 F/35 V R1 NonInverting Input 1 k J1 3 R3 49.9 Inverting Input 7 + U1 THS3001 2 J3 + 6 49.9 - R5 1 k 4 R4 49.9 C4 0.1 F R2 + J2 Output C3 6.8 F/35 V -VCC General Information 1-3 Description Figure 1-4. THS3001 Rev. A EVM Schematic VCC J1 -VCC GND VCC 1 C2 6.8 F -VCC + 2 3 VCC J2 -IN Inverting Rev. A R2 1 k R4 1 k R1 49.9 2 7 - U1 THS3001 J3 +IN Noninverting C3 0.1 F 3 R3 49.9 + 4 6 R5 49.9 J4 Out C4 0.1 F C1 6.8 F + -VCC Even though the THS3001 is a current-feedback amplifier, the gain of the EVM can easily be changed to support a particular application by simply changing the ratio of resistors R1, R4, and R5 (R1, R2, and R4 for Rev. A) as described in the following equations: + *RR + *R5R1 + *R2R4 (Rev. A) R R4 + 1 ) R4 R1 Noninverting Gain + 1 ) R ) R5 + 1 ) R2 ) R1 (Rev. A) F Inverting Gain G F G In addition, some applications, such as those for video, may require the use of 75- cable and 75- EVM input termination and output isolation resistors. Any of the resistors on the EVM board can be replaced with a resistor of a different value; however, care must be taken because the surface-mount solder pads on the board are somewhat fragile and will not survive many desoldering/soldering operations. Because of the current feedback architecture, extra care must be taken to ensure that a feedback resistor is always included in the design. In addition, there must never be a capacitor directly in the feedback path between the amplifier output and the noninverting input. Disregarding this guideline will likely result in a part that oscillates. 1-4 General Information THS3001 EVM Specifications Note: External factors can significantly affect the overall gain of the EVM. For example, connecting test equipment with 50- input impedance to the EVM output will divide the output signal level by a factor of 2 (assuming the output isolation resistor on the EVM board remains 50 ). Similar effects can occur at the input, depending upon how the input signal sources are configured. The gain equations given above assume no signal loss in either the input or the output. The EVM circuit board is an excellent example of proper board layout for high-speed amplifier designs and can be used as a guide for user application board layouts. 1.3 THS3001 EVM Specifications Supply voltage range, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 V to 15 V Supply current, ICC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5 mA Typ Input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VCC, Max Output drive, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mA, Typ Continuous power dissipation at TA = 25C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 740 mW For complete THS3001 amplifier IC specifications and parameter measurement information, and additional application information, see the THS3001 data sheet, TI Literature Number SLOS217. General Information 1-5 Using The THS3001 EVM 1.4 Using The THS3001 EVM The THS3001 EVM operates from power-supply voltages ranging from 5 V to 15 V. As shipped, the inverting input gain of the module is set to 1, the noninverting input gain is set to 2, and signal inputs on the module are terminated for 50- nominal impedance cables. An oscilloscope is typically used to view and analyze the EVM output signal. 1.4.1 Steps for THS3001 EVM 1) Ensure that all power supplies are set to OFF before making power supply connections to the THS3001 EVM. 2) Select the operating voltage for the EVM and connect appropriate split power supplies to the pads on the module marked -VCC and +VCC. 3) Connect the power supply ground to the module pad marked GND. 4) Connect an oscilloscope to the module SMA output connector (J2) through a 50- nominal impedance cable (an oscilloscope having a 50- input termination is preferred for examining very high frequency signals). 5) Set the power supply to ON. 6) Connect the signal input to either the noninverting input (J1) for a gain of 2, or to the inverting input (J3) for a gain of 1. 1.4.2 Steps for THS3001 Rev. A EVM 1) Ensure that all power supplies are set to OFF before making power supply connections to the THS3001 EVM. 2) Select the operating voltage for the EVM and connect appropriate split power supplies to J1 terminals on the module marked -VCC and +VCC. 3) Connect the power supply ground to J1 terminal marked GND. 4) Connect an oscilloscope to the module SMA output connector (J4) through a 50- nominal impedance cable (an oscilloscope having a 50- input termination is preferred for examining very high frequency signals). 5) Set the power supply to ON. 6) Connect the signal input to either the noninverting input (J3) for a gain of 2, or to the inverting input (J2) for a gain of 1. Note that each input connector is terminated with a 50- resistor to ground. With a 50- source impedance, the voltage seen by the THS3001 amplifier IC on the module will be the source signal voltage applied to the EVM. 1/2 7) Verify the output signal on the oscilloscope. Note: The signal shown on an oscilloscope with a 50- input impedance will be the actual THS3001 amplifier IC output voltage. This is due to the voltage division between the output resistor (R2) and the oscilloscope input impedance. 1/2 1-6 General Information THS3001 EVM Performance 1.5 THS3001 EVM Performance Figure 1-5 shows the typical frequency response of the THS3001 EVM using the noninverting input (G = 2). Typical values show a - 3-dB bandwidth of 340 MHz with a 15-V power supply and 260 MHz with a 5-V power supply. They also show a - 0.1-dB frequency response of 17 MHz with a 15-V power supply and 20 MHz with a 5-V power supply. Figure 1-5. THS3001 EVM Frequency Response with Gain = 2 7 6 VCC = 15 V Output Amplitude - dB 5 4 3 VCC = 5 V 2 1 0 -1 -2 VI = 200 mV RMS Rload = 150 -3 100K 1M 10M 100M 1G f - Frequency - Hz Figure 1-6 shows the typical frequency response of the THS3001 EVM using the inverting input (G = 1). Typical - 0.1 dB bandwidths are 15 MHz with a 15-V power supply and 17 MHz with a 5-V power supply. Typical - 3-dB bandwidths are 220 MHz at 15-V and 210 MHz at 5-V. Figure 1-6. THS3001 EVM Frequency Response with Inverting Gain = 1 1 0 VCC = 15 V Output Amplitude - dB -1 -2 -3 -4 VCC = 5 V -5 -6 -7 -8 VI = 200 mV RMS Rload = 150 -9 100K 1M 10M 100M 1G f - Frequency - Hz General Information 1-7 General High-Speed Amplifier Design Considerations 1.6 General High-Speed Amplifier Design Considerations The THS3001 EVM layout has been designed and optimized for use with high-speed signals and can be used as an example when designing THS3001 applications. Careful attention has been given to component selection, grounding, power supply bypassing, and signal path layout. Disregard of these basic design considerations could result in less than optimum performance of the THS3001 high-speed, current-feedback video operational amplifier. Surface-mount components were selected because of the extremely low lead inductance associated with this technology. Also, because surface-mount components are physically small, the layout can be very compact. This helps minimize both stray inductance and capacitance. Tantalum power supply bypass capacitors (C1 and C3 for original and C1 and C2 for Rev. A) at the power input pads help supply currents for rapid, large signal changes at the amplifier output. The 0.1 F power supply bypass capacitors (C2 and C4 for original version and C3 and C4 for Rev. A) were placed as close as possible to the IC power input pins in order to keep the PCB trace inductance to a minimum. This improves high-frequency bypassing and reduces harmonic distortion. A proper ground plane on both sides of the PCB should always be used with high-speed circuit design. This provides low-inductive ground connections for return current paths. In the area of the amplifier IC input pins, however, the ground plane was removed to minimize stray capacitance and reduce ground plane noise coupling into these pins. This is especially important for the inverting pin while the amplifier is operating in the noninverting mode. Because the voltage at this pin swings directly with the noninverting input voltage, any stray capacitance would allow currents to flow into the ground plane, causing possible gain error and/or oscillation. Capacitance variations at the amplifier IC inverting input pin of less than 1 pF can significantly affect the response of the amplifier. In general, it is always best to keep signal lines as short and as straight as possible. Sharp 90_ corners should be avoided -- round corners or a series of 45_ bends should be used, instead. Stripline techniques should also be incorporated when signal lines are greater than three inches in length. These traces should be designed with a characteristic impedance of either 50 or 75 , as required by the application. Such signal lines should also be properly terminated with an appropriate resistor. Finally, proper termination of all inputs and outputs should be incorporated into the layout. Unterminated lines, such as coaxial cable, can appear to be a reactive load to the amplifier IC. By terminating a transmission line with its characteristic impedance, the amplifier's load then appears to be purely resistive and reflections are absorbed at each end of the line. Another advantage of using an output termination resistor is that capacitive loads are isolated from the amplifier output. This isolation helps minimize the reduction in amplifier phase-margin and improves the amplifier stability for improved performance such as reduced peaking and settling times. 1-8 General Information Chapter 2 Reference This chapter includes a parts list and PCB layout illustrations for the THS3001 EVM and the THS3001 Rev. A EVM. Topic Page 2.1 THS3001 High-Speed Operational Amplifier EVM Parts List . . . . . . . 2-2 2.2 THS3001 EVM Board Layouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2 2.3 THS3001 Rev. A High-Speed Operational Amplifier EVM Parts List 2-4 2.4 THS3001 Rev. A EVM Board Layouts . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 Reference 2-1 THS3001 High-Speed Current-Feedback Video Operational Amplifier EVM Parts List 2.1 THS3001 High-Speed Current-Feedback Video Operational Amplifier EVM Parts List Table 2-1. THS3001 EVM Parts List Reference Description C1, C3 Capacitor, 6.8 F, 35 V, SM C2, C4 Capacitor, 0.1 F, ceramic, 10%, SM J1, J2, J3 Connector, SMA 50- vertical PC mount, throughhole R2, R3, R4 Resistor, 49.9 , 1%, 1/10 W, SM R1, R5 Resistor, 1 k, 1%, 1/10 W, SM U1 IC, THS3001, operational amplifier PCB1 PCB, THS3001 EVM Size Manufacturer/Digi-Key Part Number D Sprague 293D685X9035D2T 1206 Sprague 11C1201E104M5NT Amphenol ARF1205-ND 1206 Digi-Key P49.9CTR-ND 1206 Digi-Key P1.0KCTR-ND SOIC-8 TI THS3001 2.2 THS3001 EVM Board Layouts Board layout examples of the THS3001 EVM PCB are shown in the following illustrations. They are not to scale and appear here only as a reference. Figure 2-1. THS3001 EVM Component Placement Silkscreen and Solder Pads -VCC GND -IN R5 GND C1 R1 U1 INVERTING NONINVERTING C2 J2 GND C3 OUT J3 +VCC R4 R3 +IN GND J1 C4 R2 LITERATURE NO. SLOP 130 THS3001 EVM 2-2 -3 009957 Reference THS3001 EVM Board Layouts Figure 2-2. THS3001 EVM PC Board Layout - Component Side Figure 2-3. THS3001 EVM PC Board Layout - Back Side Reference 2-3 THS3001 Rev. A High-Speed Operational Amplifier EVM Parts List 2.3 THS3001 Rev. A High-Speed Operational Amplifier EVM Parts List Table 2-2. THS3001 Rev. A EVM Parts List Reference Description Manufacturer/Digi-Key Part Number Size C1, C2 Capacitor, 6.8 F, 35 V, SM C3, C4 Capacitor, 0.1 F, ceramic, 10%, SM J1 Terminal Block Digi-Key ED1515-ND J2, J3, J4 Connector, SMA 50- vertical PC mount, through-hole Amphenol ARF1205-ND R1, R3, R5 Resistor, 49.9 , 1%, 1/8 W, SM 1206 Digi-Key P49.9CTR-ND R2, R4 Resistor, 1 k, 1%, 1/8 W, SM 1206 Digi-Key P1.0KCTR-ND U1 IC, THS3001, operational amplifier PCB1 PCB, THS3001 Rev. A EVM D Sprague 293D685X9035D2T 1206 Sprague 11C1201E104M5NT SOIC-8 TI THS3001 2.4 THS3001 Rev. A EVM Board Layouts Board layout examples of the THS3001 Rev. A EVM PCB are shown in the following illustrations. They are not to scale and appear here only as a reference. Figure 2-4. THS3001 Rev. A EVM Component Placement Silkscreen and Solder Pads J1 -VCC J2 +VCC C1 C2 GND -IN GND R2 + INVERTING R4 +IN R1 R3 GND U1 C4 R5 J3 OUT NONINVERTING TEXAS INSTRUMENTS J4 C3 GND Rev. A + SLOP130 Rev A THS3001 EVM Board 2-4 Reference THS3001 Rev. A EVM Board Layouts Figure 2-5. THS3001 Rev. A EVM PC Board Layout - Component Side Rev. A Figure 2-6. THS3001 Rev. A EVM PC Board Layout - Back Side Rev. A Reference 2-5 2-6 Reference Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Texas Instruments: THS3001EVM